Emotional Expression and Language: A Longitudinal Study of Typically Developing Earlier and Later Talkers from 15 to 30 Months.

Children's emotional expression and language both develop during infancy and early childhood, yet these two communication systems have been studied primarily in isolation. This study focuses instead on assessing the relation between them just as productive language emerges during toddlerhood. Seventy-seven typically developing, firstborn toddlers and their families were recruited at 13 months of age. Using an extreme groups design, earlier and later talkers were selected based on their MacArthur Communicative Development Inventory production scores. Laboratory visits occurred at 15, 21, and 30 months; home visits occurred at 3-month intervals from 15 to 30 months. Observational and parent report measures assessed child language, emotional expression, temperament, and overall developmental functioning. Parents also reported on parenting stress and family life events. Overall, results support a significant relation between emotional expression and productive language that varies according to the specific emotion, a finding that may resolve earlier contradictory results in this area. Earlier talkers expressed more joy/pleasure than did later talkers, but later talkers expressed more fear and anger than did earlier talkers. Potential contributions of various child/family factors were explored. Child temperament is proposed as influencing this relation through its effects on the child's transactions with the caregiving environment.